Performance forecast for two vertical fractured wells in laterally heterogeneous gas reservoirs by boundary element method

This paper establishes a mathematical model for two vertical fractured wells in laterally heterogeneous gas reservoirs to predict and optimise production. The model is solved successfully by using the boundary element method, and the results show excellent agreements with the numerical solutions. Subsequently, typical well test curves are developed, and the crossflow occurs between the radial flow and boundary-dominated flow. Furthermore, the influences of heterogeneity and production allocation ratio are emphatically analysed. The results demonstrate that a greater share should be assigned to the well in high permeability region; otherwise, the generation of this reverse crossflow from high permeability areas to low permeability areas will produce greater energy loss. In a two-region gas reservoir with a permeability ratio of 1:2, the optimal production allocation ratio is 2:3. Compared to the reference case, the cumulative production increases are about 12.5%. In summary, a reasonable production allocation prevents significant regional pressure differences and extends the production time to obtain a higher cumulative gas production. [Received: October 28, 2024; Accepted: December 16, 2024]